JPWO2019167929A1 - Ferromagnetic layered film, spin current magnetization rotating element, magnetoresistive effect element and magnetic memory - Google Patents

Abstract

The ferromagnetic laminated film includes a plurality of first magnetic layers, at least one second magnetic layer, and at least one first nonmagnetic layer, and the first magnetic layer is the second magnetic layer or the first nonmagnetic layer. Different from the material forming the second magnetic layer, the first magnetic layer, the first non-magnetic layer, and the second magnetic layer are laminated alternately. A material combination in which an interface magnetic anisotropy is generated between the first magnetic layer and the first non-magnetic layer, and an interface magnetic anisotropy is generated between the first magnetic layer and the second magnetic layer. It is the material combination that occurs.

Description

  The present invention relates to a ferromagnetic laminated film, and also relates to a spin current magnetization rotation element, a magnetoresistive effect element and a magnetic memory having such a ferromagnetic laminated film. The present invention claims priority based on Japanese Patent Application No. 2018-033101 filed on February 27, 2018, the contents of which are incorporated herein.

  A giant magnetoresistive (GMR) element including a multilayer film of a ferromagnetic layer and a nonmagnetic layer, and a tunnel magnetoresistive (TMR) element using an insulating layer (tunnel barrier layer, barrier layer) as a nonmagnetic layer are known. .. Generally, the TMR element has a higher element resistance than the GMR element, but the magnetoresistive (MR) ratio is larger than the MR ratio of the GMR element. Therefore, attention is focused on the TMR element as an element for a magnetic sensor, a high frequency component, a magnetic head, and a nonvolatile magnetoresistive random access memory (MRAM).

  The MRAM reads and writes data by utilizing the characteristic that the element resistance of the TMR element changes when the magnetization directions of the two ferromagnetic layers sandwiching the insulating layer change. As a writing method of the MRAM, writing (magnetization reversal) is performed by using a magnetic field generated by a current, or writing (magnetization reversal) is performed by using a spin transfer torque (STT) generated by flowing a current in a stacking direction of magnetoresistive elements. ) Is known. The magnetization reversal of the TMR element using the STT is efficient from the viewpoint of energy efficiency, but it is necessary to flow a current in the stacking direction of the magnetoresistive effect element when writing data. The write current may deteriorate the characteristics of the magnetoresistive effect element.

  Further, high integration of MRAM has been recently demanded. For high integration of MRAM, it is necessary to downsize the TMR element. However, if the TMR element is downsized, the magnetization stability is reduced. If the magnetization stability decreases, the data may be unintentionally rewritten due to the influence of heat or the like. In the MRAM, such unintended rewriting of data is not allowed and it is desirable that the thermal stability is high.

  On the other hand, in recent years, attention has also been paid to a magnetization reversal method using a pure spin current generated by the spin Hall effect as a means for reducing the reversal current by a mechanism different from STT (for example, Non-Patent Document 1). SOT (spin orbital torque) is induced by a spin current generated by spin orbital interaction, a Rashba effect at the interface of different materials, break of inversion symmetry in a crystal structure, and the like. A current for inducing SOT in the magnetoresistive effect element is passed in a direction intersecting the stacking direction of the magnetoresistive effect element. That is, it is not necessary to pass a current in the stacking direction of the magnetoresistive effect element, and it is expected that the magnetoresistive effect element has a long life.

  According to Non-Patent Document 1, it is reported that the reversal current density by the SOT method is about the same as the reversal current density by the STT method. However, the reversal current density currently reported by the SOT method is insufficient for realizing high integration and low energy consumption, and there is room for improvement.

Further, for example, as described in Non-Patent Document 2, as a perpendicular magnetization film for a SOT-type magnetoresistive effect element, a ferromagnetic laminated film (for example, a ferromagnetic layer and a nonmagnetic layer) are alternately laminated. , [Co/Pt] _n ) or a ferromagnetic laminated film (for example, [Co/Ni] _n ) in which two types of ferromagnetic layers are alternately laminated. Such a ferromagnetic laminated film is also used in an STT type magnetoresistive effect element.

  A ferromagnetic laminated film in which ferromagnetic layers and non-magnetic layers are alternately laminated has high magnetic anisotropy but low saturation magnetization. On the other hand, a ferromagnetic laminated film in which two types of ferromagnetic layers are alternately laminated has high saturation magnetization but has low magnetic anisotropy. Both high magnetic anisotropy and high saturation magnetization are desirable in order to exhibit high thermal stability.

S. Fukami, T.; Anekawa, C.I. Zhang, and H.M. Ohno, Nature Nanotechnology (2016). DOI: 10.1038/NNANO. 2016.29. S. Fukami, C.I. Zhang, S.; DuttaGupta, A.; Kurekov and H.M. Ohno, Nature materials (2016). DOI: 10.1038/NMAT4566.

  The present invention has been made in view of the above problems, and an object of the present invention is to propose a new ferromagnetic laminated film that reduces the reversal current density and improves the thermal stability.

  The present invention provides the following means in order to solve the above problems.

  (1) A ferromagnetic laminated film according to a first aspect of the present invention includes a plurality of first magnetic layers, at least one second magnetic layer, and at least one first nonmagnetic layer, and Magnetic layers are alternately stacked with the second magnetic layers or the first non-magnetic layers, and the material forming the first magnetic layer is different from the material forming the second magnetic layer, and the first magnetic layer is different. And the first non-magnetic layer and the second magnetic layer are a material combination in which an interface magnetic anisotropy is generated between the first magnetic layer and the first non-magnetic layer, and the first magnetic layer It is a material combination that causes interfacial magnetic anisotropy between the layer and the second magnetic layer.

  (2) In the ferromagnetic laminated film according to the above aspect, the first magnetic layer is made of a ferromagnetic material containing one or both of Co and Fe, and the second magnetic layer is made of a ferromagnetic material containing Ni. The first non-magnetic layer may be made of a non-magnetic material containing at least one of Ti, Zr, Hf, Ru, Rh, Pd, Ag, Ir, Pt and Au.

  (3) In the ferromagnetic laminated film according to the above aspect, the first magnetic layer is made of a ferromagnetic material containing one or both of Co and Fe, and the second magnetic layer is made of a ferromagnetic material containing Ni. The first non-magnetic layer may be made of a non-magnetic material containing at least one of V, Cr, Mo, Ta and W.

  (4) In the ferromagnetic laminated film according to the above aspect, the lamination order in which the first magnetic layers are alternately laminated with the second magnetic layers or the first non-magnetic layers is the film surface of the ferromagnetic laminated film. The stacking order may be asymmetric with respect to the immediate first direction.

  (5) In the ferromagnetic laminated film according to the above aspect, the first magnetic layer, the second magnetic layer, the first magnetic layer, the first nonmagnetic layer, and the first magnetic layer are sequentially arranged in the first direction. At least one asymmetrical five-layered structure may be provided.

  (6) In the ferromagnetic laminated film according to the above aspect, at least one of the first non-magnetic layers may be thicker than both the plurality of first magnetic layers and the at least one second magnetic layer. ..

  (7) A spin current magnetization rotating element according to a second aspect of the present invention intersects the ferromagnetic laminated film according to any one of the above aspects, with respect to a first direction perpendicular to the film surface of the ferromagnetic laminated film. And a spin orbit torque wiring extending in the second direction and located in the first direction of the ferromagnetic laminated film.

  (8) A magnetoresistive effect element according to a third aspect of the present invention is a spin current magnetization rotation element according to the above aspect, a fixed layer in which the magnetization direction is fixed, the ferromagnetic laminated film and the fixed layer. And a non-magnetic spacer layer sandwiched therebetween.

  (9) A magnetoresistive effect element according to another aspect of the present invention includes the ferromagnetic laminated film according to any one of the above aspects as a fixed layer having a fixed magnetization direction, and a free layer and the ferromagnetic laminated film. And a non-magnetic spacer layer sandwiched between the free layer and the free layer.

  (10) The magnetoresistive effect element according to the aspect of (9) may further include an antiferromagnetic coupling layer and an interface ferromagnetic metal layer between the ferromagnetic laminated film and the nonmagnetic spacer layer. ..

(11) In the magnetoresistive effect element according to the above aspect, the antiferromagnetic coupling layer may include Ru, Rh, or Ir.
(12) In the magnetoresistive effect element according to the above aspect, the magnetization of the ferromagnetic laminated film may be perpendicular magnetization.
(13) In the magnetoresistive effect element according to the above aspect, the magnetization of the ferromagnetic laminated film may be inclined with respect to the film laminating direction.

  (14) A magnetic memory according to a fourth aspect of the present invention includes a plurality of magnetoresistive effect elements according to any of the above aspects.

  According to the ferromagnetic laminated film of the present invention, the reversal current density can be reduced and the thermal stability can be improved.

It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the ferromagnetic laminated film which concerns on one Embodiment of this invention. FIG. 3 is a schematic plan view for explaining the spin current magnetization rotation element according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional schematic diagram for explaining a spin current magnetization rotation element according to one embodiment of the present invention. It is a schematic diagram for explaining the spin Hall effect. It is a schematic diagram which shows an example of the cross-section of the magnetoresistive effect element which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the cross-section of the magnetoresistive effect element which concerns on one Embodiment of this invention.

  Hereinafter, preferable examples of the embodiment of the present invention will be described in detail with reference to the drawings. In the drawings used in the following description, in order to make the features of the embodiments of the present invention easier to understand, there are cases in which the characteristic portions are enlarged and schematically illustrated for convenience. Can be different. The materials, dimensions, etc. exemplified in the following description are examples, and the present invention is not limited to them, and the numbers, numerical values, amounts, ratios, characteristics, etc. may be changed as appropriate within the range where the effect is exerted. It is possible to carry out. The device according to the embodiment of the present invention may be provided with another layer within a range in which the effect of the present invention is exhibited.

(Ferromagnetic laminated film)
FIG. 1 shows a schematic view of an example of a cross-sectional structure of a ferromagnetic laminated film according to an embodiment of the present invention. In the following description, for convenience, the perpendicular direction of the film surface of the ferromagnetic laminated film or the laminating direction is defined as the first direction (z direction, thickness direction), and the longitudinal direction of the ferromagnetic laminated film is perpendicular to the first direction. A direction along the is defined as a second direction (x direction, length direction), and a direction orthogonal to both the first direction and the second direction is defined as a third direction (y direction, width direction).

  The ferromagnetic laminated film 10 shown in FIG. 1 includes a plurality of first magnetic layers 1, at least one second magnetic layer 2, and at least one first non-magnetic layer 3, and the first magnetic layer 1 is the first magnetic layer 1. The two magnetic layers 2 or the first non-magnetic layers 3 are alternately stacked.

<First magnetic layer>
The first magnetic layer 1 is made of a ferromagnetic material. A known material can be used as the ferromagnetic material forming the first magnetic layer 1. For example, a single crystal structure at room temperature is a hexagonal close-packed (hcp) structure or a metal such as cobalt (Co) showing a face centered cubic lattice (fcc), or a single crystal structure at room temperature is a body centered cubic lattice (bcc). A metal such as iron (Fe) having a structure is mentioned as a material forming the first magnetic layer 1. These metals may be used singly so as to show the above crystal structure, or may be used as an alloy (for example, a Co—Fe alloy) or a compound containing one or more of these metals and exhibiting ferromagnetism.

<Second magnetic layer>
The second magnetic layer 2 is made of a ferromagnetic material different from the ferromagnetic material forming the first magnetic layer 1. As the ferromagnetic material forming the second magnetic layer 2, a known material can be used. For example, a metal such as nickel (Ni) whose single crystal structure at room temperature shows a face-centered cubic lattice (fcc) structure or gadolinium (Gd) whose single crystal structure at room temperature is a hexagonal close-packed (hcp) structure. It can be given as a material forming the second magnetic layer 2. These metals may be used alone so as to exhibit the above crystal structure, or may be used as an alloy or compound containing one or more of these metals and exhibiting ferromagnetism. In particular, the ferromagnetic material forming the second magnetic layer 2 is selected so that interface magnetic anisotropy occurs when the second magnetic layer 2 contacts the first magnetic layer 1 to form an interface. In particular, the ferromagnetic material forming the second magnetic layer 2 is preferably selected so as to impart perpendicular magnetic anisotropy along the perpendicular direction of the ferromagnetic laminated film 10. Although not limited to these, for example, the combination of the first magnetic layer 1 and the second magnetic layer 2 may be Co/Ni, Fe/Ni, Co/Gd, Ni/Co, Ni/Fe, or the like. , Co/Ni, Fe/Ni, and Co/Gd are effective, and Co/Ni is more preferable.

<First non-magnetic layer>
The first nonmagnetic layer 3 is made of a nonmagnetic material. In particular, the non-magnetic material forming the first non-magnetic layer 3 is selected so that interfacial magnetic anisotropy occurs when the first non-magnetic layer 3 contacts the first magnetic layer 1 to form an interface. It In particular, the non-magnetic material forming the first non-magnetic layer 3 is selected so as to impart perpendicular magnetic anisotropy along the perpendicular direction of the ferromagnetic laminated film 10. A known material can be used as the non-magnetic material forming the first non-magnetic layer 3. The non-magnetic material forming the first non-magnetic layer 3 includes a metal having a hcp structure as a single crystal structure at room temperature, a metal having a fcc structure as a single crystal structure at room temperature, and a bcc having a single crystal structure at room temperature. Examples thereof include metals that exhibit a structure. The metal whose single crystal structure at room temperature exhibits the hcp structure is, for example, titanium (Ti), zirconium (Zr), hafnium (Hf), ruthenium (Ru), etc., and the single crystal structure at room temperature shows the fcc structure. The metal is, for example, rhodium (Rh), palladium (Pd), silver (Ag), iridium (Ir), platinum (Pt), gold (Au), and the like, and the single crystal structure at room temperature shows a bcc structure. Is, for example, vanadium (V), chromium (Cr), molybdenum (Mo), tantalum (Ta), tungsten (W), or the like. These metals may be used alone as shown in the above crystal structure, or may be used as a non-magnetic alloy or compound containing one or more of these metals.

  When the first magnetic layer 1, the second magnetic layer 2 and the first non-magnetic layer 3 constituting the ferromagnetic laminated film 10 are all unified so as to include a metal exhibiting an fcc structure or an hcp structure (it can be arbitrarily selected. However, for example, Co/Ni/Co/Pt/Co, Co/Ni/Co/Pd/Co), and the crystal matching in the ferromagnetic laminated film 10 are maintained, and the reversal current density is reduced and the thermal stability is improved. A high effect can be obtained for the improvement of On the other hand, when the ferromagnetic laminated film 10 contains a metal having a bcc structure (for example, when the first nonmagnetic layer 3 contains W having a bcc structure), Co-Fe-B/ which has a bcc structure in the crystal phase When the ferromagnetic laminated film 10 is used in combination with MgO/Co-Fe-B or the like, the crystal matching becomes easy and the reduction in perpendicular magnetic anisotropy due to heating can be suppressed.

  The thicknesses of the first magnetic layer 1, the second magnetic layer 2, and the first nonmagnetic layer 3 are not particularly limited, and may have a thickness of 0.2 to 3.0 nm, for example. Further, the plurality of first magnetic layers 1 that are present may not all have the same thickness. This point is the same when a plurality of second magnetic layers 2 or first non-magnetic layers 3 are present. That is, the plurality of second magnetic layers 2 and the plurality of first non-magnetic layers 3 do not have to have the same thickness. According to one embodiment, at least one of the first non-magnetic layers 3 may be thicker than both the plurality of first magnetic layers and the at least one second magnetic layer. The advantages of this configuration will be described in more detail with respect to the spin current magnetization reversal element below.

  In the ferromagnetic laminated film 10 shown in FIG. 1, the first magnetic layer 1/the second magnetic layer 2/the first magnetic layer 1/the first non-magnetic layer 3/in order from the top along the first direction (z direction). The five-layer structure of the first magnetic layer 1 (three-layer first magnetic layer 1, one second magnetic layer, one first non-magnetic layer) is laminated. In the ferromagnetic laminated film 10 shown in FIG. 1, the first magnetic layers 1 are alternately laminated with either the second magnetic layers 2 or the first nonmagnetic layers 3. An example of such a stack is Co/Ni/Co/Pt (or Pd)/Co.

  In the example shown in FIG. 1, the interface portion where the first magnetic layer 1 and the first nonmagnetic layer 3 are joined exhibits high magnetic anisotropy. On the other hand, the interface portion where the first magnetic layer 1 and the second magnetic layer 2 are joined exhibits high saturation magnetization. Therefore, the ferromagnetic laminated film 10 as a whole has both high magnetic anisotropy and high saturation magnetization, and thermal stability can be improved.

  Further, in the example shown in FIG. 1, the stacking order in which the first magnetic layer 1 and the second magnetic layer 2 or the first non-magnetic layer 3 are stacked alternately is the first layer directly on the film surface of the ferromagnetic multilayer film. It is asymmetric with respect to the direction (z direction). That is, when viewed from the first non-magnetic layer 3, the upper structure portion along the first direction (z direction) (first magnetic layer 1/second magnetic layer 2/first in order from the first non-magnetic layer 3) The magnetic layer 1) and the lower structure portion (first magnetic layer) are asymmetric. Also, when viewed from the first magnetic layer 1 at the center, the upper structural portion (second magnetic layer/first magnetic layer 1 in order from the first magnetic layer 1 at the center) and the lower structural portion (first magnetic layer at the central portion) The first non-magnetic layer 3/the first magnetic layer 1) is asymmetrical in order from the first magnetic layer 1. As described in detail below, the ferromagnetic laminated film 10 having such an asymmetric structure can be a useful structure when used in a spin current magnetization rotation element in the SOT method, and lowers the reversal current density. You can

  The ferromagnetic laminated film according to this embodiment is not limited to the five-layer structure as shown in FIG. 1 or an asymmetric structure. The ferromagnetic laminated film according to the present embodiment has another structure in which the first magnetic layer 1 and the first magnetic layer 2 or the first non-magnetic layer 3 are alternately laminated depending on the desired application and characteristics. May also have. For example, FIG. 2 is a schematic view showing another example of the cross-sectional structure of the ferromagnetic laminated film 11 according to this embodiment. The ferromagnetic laminated film 11 shown in FIG. 2 has a first magnetic layer 1/first nonmagnetic layer 3/first magnetic layer 1/first nonmagnetic layer 3 in order from the top along the first direction (z direction). /First magnetic layer 1/second magnetic layer 2/first magnetic layer 1 has a seven-layer structure (for example, Co/Pt/Co/Pt/Co/Ni/Co can be arbitrarily selected). Similar to the ferromagnetic multilayer film 10 of FIG. 1, the ferromagnetic multilayer film 11 has an upper structure portion and a lower structure portion that are asymmetrical when viewed from the first nonmagnetic layer 3 at the center.

  FIG. 3 is a schematic diagram showing another example of the cross-sectional structure of the ferromagnetic laminated film 12 having a nine-layer structure according to this embodiment. In the ferromagnetic layered film 12 shown in FIG. 3, the first magnetic layer 1/the second magnetic layer 2/the first magnetic layer 1/the second magnetic layer 2/the The stacking order of 1 magnetic layer 1/first non-magnetic layer 3/first magnetic layer 1/second magnetic layer 2/first magnetic layer 1 (for example, Co/Ni/Co/Ni/Co/ (Pt/Co/Ni/Co). Also in the ferromagnetic laminated film 12 shown in FIG. 3, the upper structure portion and the lower structure portion are asymmetrical when viewed from the first non-magnetic layer 3 including only one layer or viewed from the first magnetic layer 1 at the center.

FIG. 4 is a schematic diagram showing another example of the cross-sectional structure of the nine-layered ferromagnetic laminated film 13 according to the present embodiment. In the ferromagnetic laminated film 13 of FIG. 4, the first magnetic layer 1/the second magnetic layer 2/the first magnetic layer 1/the first nonmagnetic layer 3/the first non-magnetic layer 3/the first magnetic layer 1 in the order from the top in the first direction (z direction). The stacking order of 1 magnetic layer 1/second magnetic layer 2/first magnetic layer 1/first non-magnetic layer 3/first magnetic layer 1 (which can be arbitrarily selected, for example, Co/[Ni/Co/Pt/ Co] ₂ ) in the order of lamination. Such a laminated structure is considered to have [Ni/Co/Pt/Co] as a repeating unit, and can be expanded to Co/[Ni/Co/Pt/Co] _n having more layers than nine layers. (N is the number of repetitions greater than 2).

  FIG. 5 is a schematic view showing another example of the cross-sectional structure of the nine-layered ferromagnetic laminated film 14 according to the present embodiment. In the ferromagnetic laminated film of FIG. 5, the first magnetic layer 1/the first nonmagnetic layer 3/the first magnetic layer 1/the first nonmagnetic layer 3/the first magnetic layer 1/the first nonmagnetic layer 3/the first nonmagnetic layer 3 1 magnetic layer 1/second magnetic layer 2/first magnetic layer 1/first non-magnetic layer 3/first magnetic layer 1 (in arbitrary order, for example, Co/Pt/Co/Pt/Co /Ni/Co/Pt/Co). Even in the structure having only one second magnetic layer 2 as described above, the interface portion where the first magnetic layer 1 and the second magnetic layer 2 are bonded exhibits high saturation magnetization, and the first magnetic layer 1 and the first non-magnetic layer The interface portion where the layers 3 are joined exhibits high magnetic anisotropy, and the thermal stability can be improved.

[Modification]
Further, in the modified example of the ferromagnetic laminated film according to the present embodiment, the plurality of first magnetic layers 1 may not all be made of the same material. That is, the material forming one or some of the first magnetic layers 1 may be different from the material forming the other first magnetic layers 1. In other words, one or some of the plurality of first magnetic layers 1 may be made of a material different from the material forming the other first magnetic layers 1. Here, if one or several layers formed of a material different from the material forming the other first magnetic layer 1 is used as the third magnetic layer 4, the material can be arbitrarily selected from the above-mentioned materials. Co may be used for the first magnetic layer 1 and Fe for the third magnetic layer 4, or Fe for the first magnetic layer 1 and Co for the third magnetic layer 4. 6 and 7 are schematic views showing an example of modifications of the ferromagnetic laminated film according to the present embodiment. The ferromagnetic laminated film 15 shown in FIG. 6 has a first magnetic layer 1/second magnetic layer 2/third magnetic layer 4/first nonmagnetic layer 3/in order from the top along the first direction (z direction). The first magnetic layer 1 has a five-layer structure (which can be arbitrarily selected, for example, Co/Ni/Fe/Pt (or Pd)/Co). The ferromagnetic laminated film 16 shown in FIG. 7 has a third magnetic layer 4/a second magnetic layer 2/a first magnetic layer 1/a first non-magnetic layer 3/in order from the top in the first direction (z direction). The first magnetic layer 1 has a five-layer structure (for example, Fe/Ni/Co/Pt/Co can be arbitrarily selected).

  Similarly, when there are a plurality of second magnetic layers 2 and a plurality of first non-magnetic layers 3, the plurality of second magnetic layers 2 need not all be made of the same material, and the plurality of first non-magnetic layers 3 are not required. Does not have to be made of the same material. For example, a material different from the material forming the other second magnetic layer 2 may be used for one or some of the plurality of second magnetic layers 2. In addition, one or some of the plurality of first non-magnetic layers 3 may be changed in the material forming the other first non-magnetic layer.

  The ferromagnetic laminated film is used, for example, in a spin current magnetization rotation element. Specifically, it can be used as a free layer in a magnetoresistive effect element including a spin current magnetization rotation element. When the ferromagnetic laminated film is used as a free layer, an additional ferromagnetic metal film such as a Co-Fe-B alloy is provided between the ferromagnetic laminated film and the nonmagnetic spacer layer in order to increase the magnetoresistive effect. May be inserted. Furthermore, a nonmagnetic insertion layer that cuts the crystal growth of the ferromagnetic laminated film and the additional ferromagnetic metal film may be inserted between the ferromagnetic laminated film and the additional ferromagnetic metal film. Further, more broadly, the ferromagnetic laminated film can be used also as a fixed layer in a general magnetoresistive effect element such as an SOT method or an STT method. Hereinafter, embodiments of the element using the ferromagnetic laminated film according to the present embodiment will be described.

(Spin current magnetization rotating element)
FIG. 8 shows a schematic diagram of an example of the spin current magnetization rotation element according to the embodiment of the present invention. 8A is a plan view, and FIG. 8B is a cross-sectional view taken along line XX which is the center line in the width direction of the spin orbit torque wiring 120 of FIG. 8A.

  The spin current magnetization rotation element 100 shown in FIG. 8 includes a ferromagnetic laminated film 110 whose magnetization direction changes, and a second laminated layer 110 which intersects the first direction (z direction) which is the perpendicular direction of the ferromagnetic laminated film 110. A spin orbit torque wiring 120 extending in the direction (x direction) and located in the first direction of the ferromagnetic laminated film 110. In FIG. 8, the ferromagnetic laminated film 110 is shown joined to the spin orbit torque wiring 120, but other layers or the like are included between the ferromagnetic laminated film 110 and the spin orbit torque wiring 120. May be. Further, in FIG. 8B, a power supply 130 for energizing the spin orbit torque wiring 120 when rotating the magnetization of the ferromagnetic laminated film 110 is also shown.

  The spin current magnetization rotation element 100 of this embodiment, that is, the element that rotates the magnetization of the ferromagnetic material by the SOT effect by the spin current is used in the magnetoresistive effect element that reverses the magnetization of the ferromagnetic material by only the SOT by the spin current. You can In this specification, an element that rotates the magnetization of a ferromagnetic material by the SOT effect due to the spin current is particularly called a spin current magnetization reversal element. On the other hand, the spin current magnetization rotation element of the present embodiment can also be used as an assisting means or a main force means of magnetization reversal of a ferromagnetic body in a conventional magnetoresistive effect element utilizing STT.

<Ferromagnetic layered film>
The ferromagnetic laminated film 110 is any one of the ferromagnetic laminated films according to the present invention, for example, the ferromagnetic laminated films 10 to 16 shown in FIGS. 1 to 7, and preferably shown in FIGS. 1 to 3. It is an asymmetric ferromagnetic laminated film such as the ferromagnetic laminated films 10 to 12.

<Spin orbit torque wiring>
The spin orbit torque wiring 120 is made of a material that generates a spin current by the spin Hall effect when a current flows and induces a spin orbit torque. In other words, the material of the spin orbit torque wiring 120 may be any material that can generate a spin current in the spin orbit torque wiring 120. Therefore, the material of the spin-orbit torque wiring 120 is not limited to a material composed of a single element, but a material composed of a material in which a spin current is generated and a material composed of a material in which a spin current is not generated. May be

  The spin Hall effect is a phenomenon in which a pure spin current is induced in a direction orthogonal to the direction of the current based on the spin-orbit interaction when a current is applied to the material.

  FIG. 9 is a schematic diagram for explaining the spin Hall effect. FIG. 9 is a cross-sectional view of the spin orbit torque wiring 120 in FIGS. 8A and 8B taken along the x direction. The mechanism by which the pure spin current is generated by the spin Hall effect will be described based on FIG.

  As shown in FIG. 9, when the current I is passed in the extending direction of the spin orbit torque wiring 120, the first spin S1 oriented toward the front side of the paper and the second spin S2 oriented toward the back of the paper are orthogonal to the current, respectively. Can be bent in any direction. The ordinary Hall effect and the spin Hall effect are common in that the moving (moving) charge (electron) can bend the moving (moving) direction, but the ordinary Hall effect is that charged particles moving in a magnetic field generate Lorentz force. In contrast to the fact that the direction of motion can be bent by receiving it, the spin Hall effect is very different in that the moving direction can be bent only by the movement of electrons (only the flow of current) without the presence of a magnetic field.

  In a non-magnetic material (a material that is not a ferromagnetic material), the number of electrons in the first spin S1 is equal to the number of electrons in the second spin S2. The number of electrons of the second spin S2 to go is equal. Therefore, the current as a net flow of charge is zero. The spin current without this current is particularly called a pure spin current.

  When an electric current is passed through the ferromagnetic material, the first spin S1 and the second spin S2 are bent in the opposite directions. On the other hand, in the ferromagnetic material, either the first spin S1 or the second spin S2 is large. Therefore, when an electric current is passed through the ferromagnetic material, a net flow of electric charges is generated as a result (a voltage is generated), which is different from when an electric current is passed through the non-magnetic material. Therefore, the material of the spin orbit torque wiring 120 is preferably a non-magnetic material.

  The non-magnetic material of the spin orbit torque wiring 120 may include a non-magnetic heavy metal. Here, the heavy metal means a metal having a specific gravity of yttrium or more. The spin orbit torque wiring 120 may be composed only of non-magnetic heavy metal.

  In this case, the nonmagnetic heavy metal is preferably a nonmagnetic metal having an atomic number of 39 or more and a large atomic number having d or f electrons in the outermost shell. This is because a non-magnetic metal having an atomic number of 39 or more and a large atomic number having d electrons or f electrons in the outermost shell has a large spin-orbit interaction that causes the spin Hall effect. The spin orbit torque wiring 120 may be composed only of a nonmagnetic metal having a large atomic number of 39 or more, which has d electrons or f electrons in the outermost shell. Examples of such nonmagnetic metals include Mo, Ru, Rh, Pd, Ta, W, Ir, Pt, Au, and Bi.

  Normally, when an electric current is passed through a metal, all electrons move in the opposite direction of the electric current, regardless of the spin direction. On the other hand, a non-magnetic metal having a large atomic number having d-electrons or f-electrons in the outermost shell has a large spin-orbit interaction, and therefore, the direction in which electrons move due to the spin Hall effect depends on the direction of electron spin. Pure spin current Js is likely to occur.

Here, when the electron flow of the first spin S1 is J _↑ , the electron flow of the second spin S2 is J _↓ , and the spin current is _JS , _JS =J _↑ −J _↓ . In FIG. 2, J _S flows as a pure spin current in the upward direction in the figure. Here, J _S is a flow of electrons having a polarizability of 100%.

  In the spin current magnetization rotation element 100 of the present embodiment, the current is passed through the spin orbit torque wiring 120 to generate a spin current, and the spin current is diffused into the ferromagnetic laminated film 110 in contact with the spin orbit torque wiring 120. With the configuration, the spin rotation torque (SOT) effect due to the spin current causes the magnetization rotation of the ferromagnetic laminated film 110. If the SOT effect is sufficiently large, the magnetization of the ferromagnetic laminated film 110 is reversed. The spin current magnetization rotating element of this embodiment in which the magnetization of the ferromagnetic laminated film 110 is reversed can be particularly called a spin current magnetization reversing element.

  Further, in the spin current magnetization rotation element 100 of this embodiment, SOT can be induced even in the ferromagnetic laminated film 110. That is, when a current is passed through the spin orbit torque wiring 120, a current also flows through the ferromagnetic laminated film 110 that is bonded to the spin orbit torque wiring 120. The ferromagnetic laminated film 110 includes at least one first nonmagnetic layer 3, and the first nonmagnetic layer 3 may include a heavy metal having a strong spin-orbit interaction such as Pt, Pd, Ag, and Mo. Therefore, a spin current is generated in the first nonmagnetic layer 3. The ferromagnetic laminated film 110 may have an asymmetric structure as shown in FIGS. When the spin current generated in the first nonmagnetic layer 3 diffuses into the asymmetric structure, an additional spin orbital torque effect that causes magnetization rotation occurs. Therefore, in the spin current magnetization rotation element 100 of the present embodiment, the reversal current can be further reduced as compared with the case where the spin orbit torque effect is generated only in the spin orbit torque wiring 120.

  In one embodiment, as described above, at least one of the first non-magnetic layers 3 included in the ferromagnetic laminated film 110 is formed by any one of the plurality of first magnetic layers 1 and at least one second magnetic layer 2. Can also be thicker. In such a configuration, when the current flows into the ferromagnetic laminated film 110, the current flows most in the first non-magnetic layer 3, and the amount of heavy metal contained in the thick first non-magnetic layer 3 increases. By this, the spin current can be efficiently generated.

  The spin current magnetization rotation element of this embodiment can be applied to a magnetoresistive effect element as described later. However, the application is not limited to the magnetoresistive effect element, and can be applied to other applications. Other applications include, but are not limited to, a spatial light modulator that spatially modulates incident light by using a magneto-optical effect by disposing a spin current magnetization rotation element in each pixel. The magnetic field applied to the easy axis of magnetization of the magnet may be replaced with SOT in order to avoid the effect of hysteresis due to the coercive force of the magnet in the magnetic sensor.

(Magnetoresistive effect element)
A magnetoresistive effect element according to an embodiment of the present invention includes the spin current magnetization rotation element 100 of the present embodiment.

  FIG. 10 schematically shows a cross-sectional structure of a magnetoresistive effect element 200 according to an embodiment including the spin current magnetization rotation element 100 of the present embodiment.

  The magnetoresistive effect element 200 shown in FIG. 10 is sandwiched between the spin current magnetization rotation element 100 of the present embodiment, the fixed layer 230 whose magnetization direction is fixed, and the ferromagnetic laminated film 110 and the fixed layer 230. And a non-magnetic spacer layer 240. Here, since the spin current magnetization rotating element has the ferromagnetic laminated film 110 and the spin orbit torque wiring 120, the magnetoresistance effect element 200 shown in FIG. It can be paraphrased to have and.

  The magnetoresistive effect element 200 according to the embodiment of the present invention can be configured to perform the magnetization reversal of the magnetoresistive effect element only by the SOT by the spin current by including the spin orbit torque wiring 120, or the conventional magnetoresistive effect element. A magnetoresistive effect element using STT can also be configured to use SOT by spin current together.

  In FIG. 10, a wiring 250 for passing a current in the stacking direction of the magnetoresistive effect element 200 and a substrate 260 for manufacturing the magnetoresistive effect element 200 are also shown.

<Magnetoresistive element part>
The magnetoresistive effect element part 205 includes a ferromagnetic laminated film 110 of the present embodiment used as a free layer (also called a free layer, a storage layer, a recording layer, etc.) whose magnetization direction changes, and a fixed layer whose magnetization direction is fixed. 230 (also referred to as a pinned layer, a pinned layer, etc.) and a non-magnetic spacer layer 240 sandwiched between the ferromagnetic laminated film 110 and the fixed layer 230.

  In the magnetoresistive effect element part 205, the magnetization of the fixed layer 230 is fixed in one direction, and the magnetization direction of the ferromagnetic laminated film 110 relatively changes. When applied to a coercive force difference type (pseudo spin valve type) MRAM, the coercive force of the fixed layer 230 is larger than the coercive force of the free layer (ferromagnetic laminated film 110). When applied to an exchange bias type (spin valve) MRAM, the magnetization direction of the fixed layer 230 is fixed by exchange coupling with an additional antiferromagnetic layer.

  When the nonmagnetic spacer layer 240 is made of an insulator, the magnetoresistive effect element part 205 is a tunneling magnetoresistive (TMR) element. When the non-magnetic spacer layer 240 is made of metal, it is a giant magnetoresistive (GMR) element.

  As the magnetoresistive effect element section 205 included in the present embodiment, a known structure of the magnetoresistive effect element section can be used. The magnetoresistive effect element part 205 is not limited to this example, but each layer other than the ferromagnetic laminated film 110 may be composed of a plurality of layers, for example, and the magnetization direction of the fixed layer 230 is fixed. Other layers such as an antiferromagnetic layer may be provided.

The ferromagnetic laminated film 110 as the free layer is preferably a perpendicular magnetization film having a magnetization perpendicular to the film surface. Therefore, the fixed layer 230 is preferably configured as a perpendicular magnetization film whose magnetization direction is perpendicular to the layer.
Further, the magnetization of the ferromagnetic laminated film 110 is effective even if it is inclined with respect to the film laminating direction. If the magnetization direction of the ferromagnetic laminated film 110 used as the free layer is inclined, the magnetization reversal current value can be lowered when used as SOT and STT. That is, the current required for reversing the magnetization can be reduced. Further, even when used as the SOT, if the magnetization direction of the ferromagnetic laminated film 110 is inclined, the magnetization reversal can be performed without a magnetic field.

  A known material can be used as the material of the fixed layer 230. For example, a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, and an alloy containing one or more of these metals and exhibiting ferromagnetism can be used. Alternatively, an alloy containing these metals and at least one element of B, C, and N can be used. Specifically, Co-Fe, Co-Fe-B, and the like are listed as the material of the fixed layer 230.

Further, as the material of the fixed layer 230, it is preferable to use a Heusler alloy such as Co ₂ FeSi in order to obtain higher output. The Heusler alloy is an alloy containing an intermetallic compound having a chemical composition of XYZ or X ₂ YZ, where X, Y and Z are the following. Here, X is a transition metal element or a noble metal element of Co, Fe, Ni, or Cu group on the periodic table. Y is a transition metal of the group Mn, V, Cr or Ti, and can also take the elemental species of X. Z is a typical element of Group III to Group V. That is, although not limited to these, examples of the Heusler alloy include Co ₂ FeSi, Co ₂ MnSi, and Co ₂ Mn _1-a Fe _a Al _b Si _1-b .

  In order to increase the coercive force of the fixed layer 230 with respect to the ferromagnetic laminated film 110, IrMn, PtMn are used as a layer (pinning layer) in contact with the fixed layer 230 on the surface opposite to the surface in contact with the non-magnetic spacer layer 240. A layer of antiferromagnetic material such as Furthermore, in order to prevent the leakage magnetic field of the fixed layer 230 from affecting the ferromagnetic laminated film 110, a synthetic ferromagnetic coupling structure may be used.

A known material can be used for the non-magnetic spacer layer 240. For example, when the nonmagnetic spacer layer 240 is made of an insulator (that is, when it is a tunnel barrier layer), Al ₂ O ₃ , SiO ₂ , MgO, MgAl ₂ O ₄ or the like is used as its material. it can. In addition to these, a material in which a part of Al, Si, Mg is replaced with Zn, Be or the like can be used. Among these, MgO and MgAl ₂ O ₄ are materials that can realize a coherent tunnel, and therefore spins can be efficiently injected. When the nonmagnetic spacer layer 240 is made of metal, Cu, Au, Ag, or the like can be used as the material.

  Moreover, the magnetoresistive effect element part 205 may further have other layers. Although not limited to these, for example, an underlayer may be further provided on the surface of the ferromagnetic laminated film 110 opposite to the nonmagnetic spacer layer 240. Further, a cap layer may be further provided on the surface of the fixed layer 230 opposite to the nonmagnetic spacer layer 240.

<Wiring>
The wiring 250 is electrically connected to the fixed layer 230. For example, in FIG. 10, the wiring 250, the spin orbit torque wiring 120, and a power supply (not shown) constitute a closed circuit, and a current is passed in the stacking direction of the magnetoresistive effect element section 205.

  The wiring 250 is not particularly limited as long as the material has high conductivity. Although not limited to these, for the wiring 250, for example, aluminum, silver, copper, gold, or the like can be used.

<Substrate>
The substrate 260 preferably has excellent flatness. That is, if the other conditions are the same, smaller ones are preferable to larger ones. The substrate 260 can use, for example, Si, AlTiC or the like as a material in order to obtain a surface having excellent flatness.

  An underlayer (not shown) may be formed on the surface of the magnetoresistive effect element section 205 on the spin orbit torque wiring 120 side. When the base layer is provided, crystallinity such as crystal orientation and crystal grain size of each layer stacked over the substrate 260 can be controlled.

  Various materials can be used for the underlayer. For example, as one example, the underlayer has a (001)-oriented NaCl structure, and at least one selected from the group consisting of Ti, Zr, Nb, V, Hf, Ta, Mo, W, B, Al, and Ce. A nitride layer containing one element can be used.

As another example, a layer of a (002)-oriented perovskite-based conductive oxide represented by a composition formula of XYO ₃ can be used as the underlayer. Here, the site X contains at least one element selected from the group of Sr, Ce, Dy, La, K, Ca, Na, Pb, Ba, and the site Y contains Ti, V, Cr, Mn, Fe, Co. , Ni, Ga, Nb, Mo, Ru, Ir, Ta, Ce, Pb, and at least one element selected from the group.

  As another example, an oxide layer having a (001)-oriented NaCl structure and containing at least one element selected from the group consisting of Mg, Al, and Ce can be used as the underlayer.

  As another example, the underlayer has a (001)-oriented tetragonal structure or a cubic structure, and includes Al, Cr, Fe, Co, Rh, Pd, Ag, Ir, Pt, Au, Mo, and W. A layer containing at least one element selected from the group can be used.

  Further, the base layer is not limited to one layer, and a plurality of layers of the above examples may be laminated. By devising the structure of the underlayer, the crystallinity of each layer can be increased and the magnetic characteristics can be improved.

  In addition, as described above, in order to increase the magnetoresistive effect, an additional ferromagnetic metal film such as a Co—Fe—B alloy is inserted between the ferromagnetic laminated film 110 and the nonmagnetic spacer layer 240. Good. Further, a non-magnetic insertion layer for cutting the crystal growth of the ferromagnetic laminated film 110 and the additional ferromagnetic metal film may be inserted between the ferromagnetic laminated film 110 and the additional ferromagnetic metal film. Good. Although the structure of the magnetoresistive effect element part 205 is not limited to these, for example, the ferromagnetic laminated film 110/nonmagnetic insertion layer/additional ferromagnetic metal film/nonmagnetic spacer layer are arranged in order from the side closer to the wiring 250. 240/fixed layer 230.

  The magnetoresistive effect element shown in the figure is shown as a so-called top pin structure in which the fixed layer 230 is located on the side farther from the substrate 260 (the upper part of the drawing), but the structure of the magnetoresistive effect element is not particularly limited. Alternatively, a bottom pin structure in which the fixing layer is located on the side closer to the substrate (lower part of the drawing) may be used.

(Magnetoresistive effect element according to another embodiment)
In the magnetoresistive effect element including the spin current magnetization rotation element, the ferromagnetic laminated film of this embodiment is used as the free layer. However, the ferromagnetic laminated film according to the present embodiment can also be used as the fixed layer in the magnetoresistive effect element. The magnetoresistive effect element using the ferromagnetic laminated film of the present embodiment as the fixed layer is considered to be based on only the conventional STT method. On the other hand, the magnetoresistive effect element 200 using the ferromagnetic laminated film of the present embodiment shown in FIG. 10 as a free layer can be either the SOT method only or the method using both the STT method and the SOT method.

  FIG. 11 is a schematic view schematically showing an example of a cross-sectional structure of the magnetoresistive effect element 300 when using such a ferromagnetic laminated film of this embodiment as a fixed layer. Although FIG. 11 shows a bottom pin structure in which the fixing layer is located at the bottom of the drawing, it may be a top pin structure in which the fixing layer is located at the top of the drawing.

  In the present embodiment, the magnetoresistive effect element 300 includes a ferromagnetic laminated film 310 used as a fixed layer whose magnetization direction is fixed, a free layer 320 whose magnetization direction is changed, and a ferromagnetic laminated film and a fixed layer. And a non-magnetic spacer layer 330 sandwiched between. The ferromagnetic laminated film 310, the free layer 320, and the nonmagnetic spacer layer 330 are combined with the layers appropriately added to form the magnetoresistive effect element portion 305.

  In FIG. 11, the magnetoresistive effect element portion 305 is illustrated as optionally further including an antiferromagnetic coupling layer 340 and an interface ferromagnetic metal layer 350. Further, FIG. 11 also shows a first wiring (lower wiring) 360 electrically connected to the ferromagnetic laminated film 310 and a second wiring (upper wiring) 370 electrically connected to the free layer 320. ing.

<Ferromagnetic layered film>
The ferromagnetic laminated film 310 is used as a fixed layer whose magnetization is fixed. The ferromagnetic laminated film 310 is the ferromagnetic laminated film according to the above embodiment. That is, the ferromagnetic laminated film 310 is, for example, one of the ferromagnetic laminated films 10 to 16 shown in FIGS. 1 to 7, and may be the ferromagnetic laminated film 10 shown in FIG. It may be the ferromagnetic laminated film 11 shown. As described above, when the magnetoresistive effect element is applied to a coercive force difference type (pseudo spin valve type) MRAM, the coercive force of the fixed layer is larger than that of the free layer. To be done. Here, the ferromagnetic laminated film 310 used as the fixed layer has both high magnetic anisotropy and high saturation magnetization. Further, the ferromagnetic laminated film 310 used as the fixed layer is excellent in coercive force and, in turn, excellent in thermal stability.

  The known magnetoresistive effect element structure can also be used in the magnetoresistive effect element including the ferromagnetic laminated film of the present embodiment as the fixed layer. For example, each layer other than the ferromagnetic layered film 310 may have a structure including a plurality of layers.

The ferromagnetic laminated film 310 used as the fixed layer is preferably a perpendicular magnetization film having a magnetization perpendicular to the film surface. Therefore, the free layer 320 is also configured as a perpendicular magnetization film whose magnetization direction is perpendicular to the layer. When the magnetization of the ferromagnetic layered film 310 used as the fixed layer is perpendicular magnetization, there is no need to use a pinning layer using an antiferromagnetic material, so that it can withstand a heat treatment of 350° C. or higher and has a high magnetic resistance. It is preferable because the effect can be obtained.
The direction of magnetization of the ferromagnetic laminated film 310 is also preferably inclined with respect to the film laminating direction. When the magnetization direction of the ferromagnetic laminated film 310 used as the fixed layer of the SOT is inclined with respect to the film laminating direction, the leakage magnetic field from the ferromagnetic laminated film 310 to the free layer 320 is inclined, and the magnetic field is not applied. Magnetization reversal becomes possible.

  A ferromagnetic material can be applied as the material of the free layer 320. Further, as the material of the free layer 320, a soft magnetic material can be particularly preferably applied. The material of the free layer is not limited to these, but includes, for example, metals selected from the group consisting of Cr, Mn, Co, Fe and Ni, alloys containing one or more of these metals, these metals and B. An alloy containing at least one element of C, C, and N can be used. Among the above-mentioned materials, the free layer 320 includes Co-Fe, Co-Fe-B, and Ni-Fe, and Co-Fe-B is particularly preferable.

  The material of the nonmagnetic spacer layer 330 is the same as the material of the nonmagnetic spacer layer 240. The material of the nonmagnetic spacer layer 330 is preferably MgO, for example.

  The magnetoresistive effect element part 305 may further include an antiferromagnetic coupling layer 340 and an interface ferromagnetic metal layer 350 to form a synthetic antiferromagnetic (SAF) structure. In such a SAF structure, the ferromagnetic laminated film 310 and the interface ferromagnetic metal layer 350 are antiferromagnetically coupled by the RKKY interaction through the antiferromagnetic coupling layer 340, and the magnetizations of these two ferromagnets are coupled. The directions are antiparallel to each other.

  The antiferromagnetic coupling layer 340 is a nonmagnetic layer. The material forming the antiferromagnetic coupling layer is, for example, Ru, Rh, or Ir which is a nonmagnetic metal.

  The interface ferromagnetic metal layer 350 is a ferromagnetic layer and is also called a reference layer. The material forming the interface ferromagnetic metal layer 350 may be the same as the material forming the free layer 320. The material forming the interface ferromagnetic layer 350 is preferably Co-Fe-B.

  The first wiring (lower wiring) 360 is electrically connected to the ferromagnetic laminated film 310. The second wiring (upper wiring) 370 is electrically connected to the free layer 320. In FIG. 11, the first wiring 360, the second wiring 370, and the power supply (not shown) form a closed circuit, and a current flows in the stacking direction of the magnetoresistive effect element 305.

  The first wiring 360 is not particularly limited as long as the material has high conductivity. The first wiring 360 may be, for example, aluminum, silver, copper, gold, or the like.

  The second wiring 370 is also not particularly limited as long as it is a material having high conductivity. The same material as the first wiring 360 can be used for the second wiring 370, and the material of the first wiring 360 and the material of the second wiring 370 may be the same material. When the material of the first wiring 360 and the material of the second wiring 370 are the same, the magnetoresistive effect element 300 performs the magnetization reversal only by the conventional STT method, for example. As an alternative embodiment, the second wiring 370 may be configured as the spin orbit torque wiring as described above, and the magnetization reversal by the SOT method may be used in the magnetoresistive effect element 300.

(Method for manufacturing ferromagnetic laminated film)
The method for manufacturing the ferromagnetic laminated film of the present embodiment is not particularly limited, and a known film forming method can be used. As the film forming method, for example, resistance heating evaporation, electron beam evaporation, molecular beam epitaxy (MBE) method, ion plating method, ion beam deposition method, sputtering method, etc. are used as physical vapor deposition (PVD) method. be able to. Alternatively, as the chemical vapor deposition (CVD) method, a thermal CVD method, a photo CVD method, a plasma CVD method, a metal organic chemical vapor deposition (MOCVD) method, an atomic layer deposition (ALD) method, or the like can be used.

  The obtained ferromagnetic laminated film is preferably annealed. The layer formed by reactive sputtering is amorphous and needs to be crystallized.

  The ferromagnetic laminated film manufactured by the annealing treatment has an improved magnetoresistive ratio as compared with the ferromagnetic laminated film manufactured without the annealing treatment.

  As the annealing treatment, heating is performed in an inert atmosphere such as Ar at a temperature of 300° C. or more and 500° C. or less for a time of 5 minutes or more and 100 minutes or less, and then a magnetic field of 2 kOe or more and 10 kOe or less is applied to 100° C. It is preferable to heat at a temperature of not less than 500° C. and not more than 1 hour and not more than 10 hours.

  The method for forming the ferromagnetic laminated film into a predetermined shape is not particularly limited, but a processing means such as photolithography can be used. First, after stacking a ferromagnetic laminated film, a resist is applied thereon. Then, the resist of a predetermined portion is cured and the resist of an unnecessary portion is removed. The portion where the resist is hardened serves as a protective film for the ferromagnetic laminated film. The hardened portion of the resist matches the shape of the finally obtained ferromagnetic laminated film.

  Then, the surface on which the protective film is formed is subjected to treatments such as ion milling and reactive ion etching (RIE). The portion where the protective film is not formed is removed to obtain a ferromagnetic laminated film having a predetermined shape.

  The present invention is not necessarily limited to the configurations and manufacturing methods according to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. You may.

(Magnetic memory)
The magnetic memory (MRAM) of this embodiment includes a plurality of magnetoresistive effect elements of this embodiment.

1... 1st magnetic layer, 2... 2nd magnetic layer, 3... 1st non-magnetic layer, 4... 3rd magnetic layer, 10, 11, 12, 13, 14, 15, 16, 110, 310... Ferromagnetic lamination Film, 100... Spin current magnetization rotating element, 120... Spin orbit torque wiring, 130... Power supply, 200, 300... Magnetoresistive effect element, 205, 305... Magnetoresistive effect element part, 230... Fixed layer, 240, 330... Non Magnetic spacer layer, 250... Wiring, 260... Substrate, 320... Free layer, 340... Antiferromagnetic coupling layer, 350... Interface ferromagnetic metal layer, 360... First wiring, 370... Second wiring

Claims (14)

A plurality of first magnetic layers,
At least one second magnetic layer,
At least one first non-magnetic layer,
The first magnetic layer is alternately laminated with the second magnetic layer or the first non-magnetic layer, and the material forming the first magnetic layer is different from the material forming the second magnetic layer,
The first magnetic layer, the first non-magnetic layer, and the second magnetic layer are a material combination in which an interface magnetic anisotropy is generated between the first magnetic layer and the first non-magnetic layer, A ferromagnetic laminated film, which is a material combination that causes interfacial magnetic anisotropy between the first magnetic layer and the second magnetic layer. The first magnetic layer is made of a ferromagnetic material containing one or both of Co and Fe,
The second magnetic layer is made of a ferromagnetic material containing Ni,
The ferromagnetic stack according to claim 1, wherein the first non-magnetic layer is made of a non-magnetic material containing at least one of Ti, Zr, Hf, Ru, Rh, Pd, Ag, Ir, Pt and Au. film. The first magnetic layer is made of a ferromagnetic material containing one or both of Co and Fe,
The second magnetic layer is made of a ferromagnetic material containing Ni,
The ferromagnetic laminated film according to claim 1, wherein the first nonmagnetic layer is made of a nonmagnetic material containing at least one of V, Cr, Mo, Ta, and W.   The stacking order in which the first magnetic layers are stacked alternately with the second magnetic layers or the first non-magnetic layers is a stacking order that is asymmetric with respect to the first direction that is perpendicular to the film surface of the ferromagnetic stacked film. The ferromagnetic laminated film according to any one of claims 1 to 3.   At least one asymmetric five-layer structure in which the first magnetic layer, the second magnetic layer, the first magnetic layer, the first non-magnetic layer, and the first magnetic layer are sequentially stacked in the first direction. The ferromagnetic laminated film according to claim 4, comprising.   6. The ferromagnetic stack according to claim 1, wherein at least one of the first non-magnetic layers is thicker than both of the plurality of first magnetic layers and the at least one second magnetic layer. film. A ferromagnetic laminated film according to any one of claims 1 to 6,
A spin orbit torque wiring extending in a second direction intersecting with a first direction directly in the plane of the ferromagnetic laminated film and located in the first direction of the ferromagnetic laminated film. Magnetization rotating element. A spin current magnetization rotation element according to claim 7,
A fixed layer whose magnetization direction is fixed,
A magnetoresistive effect element comprising a non-magnetic spacer layer sandwiched between the ferromagnetic laminated film and the fixed layer. A ferromagnetic laminated film according to any one of claims 1 to 6 is provided as a fixed layer whose magnetization direction is fixed,
The free layer,
The magnetoresistive effect element further comprising a non-magnetic spacer layer sandwiched between the ferromagnetic laminated film and the free layer.   The magnetoresistive effect element according to claim 9, further comprising an antiferromagnetic coupling layer and an interface ferromagnetic metal layer between the ferromagnetic laminated film and the nonmagnetic spacer layer.   The magnetoresistive effect element according to claim 10, wherein the antiferromagnetic coupling layer contains Ru, Rh, or Ir.   12. The magnetoresistive effect element according to claim 8, wherein the magnetization of the ferromagnetic laminated film is perpendicular magnetization.   12. The magnetoresistive effect element according to claim 8, wherein the magnetization of the ferromagnetic laminated film is inclined with respect to the laminating direction.   A magnetic memory comprising a plurality of the magnetoresistive effect elements according to claim 8.

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